str1 ="hello world"
str2 ='hello world'
str3 ='''hello world'''
print(str1)
print(str2)
print(str3)
print('hel\'lo world') #\是转义符
print('123---{0}'.format(4) )
str1='hello'
print(f'123----{str1}')


for i in range(0,101,2):
    print("==========开始下载==========")
    if i==100:
        print("下载完成")
    else:
        str4="*"*(i//2)+"."*((100-i)//2)
        print(f'{i}%[{str4}]')
